A typical 10-month-old boy weighs about 20.2 pounds (9.2 kg), and a typical 10-month-old girl weighs about 18.7 pounds (8.5 kg). These are 50th percentile values from the WHO growth standards, meaning half of all babies at this age weigh more and half weigh less. The healthy range is wide, though, and where your baby falls on the growth curve matters more than any single number.
Average Weight by Sex
Boys and girls follow slightly different growth curves from birth. At 10 months, the normal range spans several pounds in either direction from the average. A boy at the 25th percentile weighs around 18.5 pounds, while one at the 75th percentile is closer to 22 pounds. For girls, the 25th percentile is about 17.2 pounds and the 75th is around 20.3 pounds.
The WHO growth standards define the outer boundaries of typical growth at roughly the 2nd and 98th percentiles. A 10-month-old boy below about 16.7 pounds or above 25.5 pounds falls outside those cutoffs, as does a girl below 15.4 pounds or above 24 pounds. Pediatricians use these thresholds as flags for further evaluation, not as automatic diagnoses.
Why the Range Is So Wide
Genetics play the biggest role. Tall, larger-framed parents tend to have bigger babies, and the reverse is true for smaller parents. Birth weight also sets a starting trajectory: babies born larger often stay in the upper percentiles, and babies born smaller often stay lower. Both patterns are completely normal as long as the baby tracks consistently along their own curve.
By 10 months, most babies are crawling and many are pulling themselves up to stand or cruise along furniture. This burst of physical activity burns more calories, so weight gain often slows noticeably compared to the first six months. Some babies even thin out a bit as they become more mobile. Premature babies may also weigh less at 10 months, since their growth is typically tracked against their corrected age rather than their birth date.
How Fast Weight Should Increase
Between 9 and 12 months, healthy babies typically gain 2 to 4 ounces per week. That’s a big slowdown from early infancy, when gaining 5 to 7 ounces a week was common. This deceleration is normal and expected. It reflects the shift from rapid early growth to a period where motor development takes center stage.
What matters most isn’t the weekly number but the overall trend. A baby who has tracked along the 30th percentile for months and continues doing so is growing perfectly well, even if they weigh less than a friend’s baby of the same age. A sudden drop across two or more percentile lines, on the other hand, is something pediatricians take seriously, because it can signal feeding difficulties, illness, or other issues worth investigating.
Feeding and Calories at 10 Months
A 10-month-old needs roughly 750 to 900 calories per day. About 400 to 500 of those calories should still come from breast milk or formula, which works out to approximately 24 ounces a day. The remaining calories come from solid foods, and by this age most babies are eating three small meals with one or two snacks.
This balance matters for weight. Babies who fill up on low-calorie solids (like plain rice cereal or watery purees) without enough breast milk or formula may not gain weight as expected. On the flip side, babies who refuse solids and rely entirely on milk may miss out on iron and other nutrients that support healthy growth. A mix of both, gradually shifting toward more solids over the coming months, supports steady weight gain.
How to Weigh Your Baby at Home
If you want to track your baby’s weight between pediatrician visits, a digital baby scale gives the most accurate reading. Weigh your baby naked, before a feeding, and at roughly the same time of day each time. Place the scale on a hard, flat surface like a kitchen or bathroom floor, not on carpet. Make sure your baby’s legs don’t hang off the edge of the scale, since that throws off the reading. If the baby squirms, wait for the number to stabilize before recording it.
Without a baby scale, you can use a regular bathroom scale. Weigh yourself first and write it down. Then pick up your undressed baby, step on the scale again, and subtract your weight from the combined number. This method is less precise, especially for tracking small weekly changes, but it gives a reasonable estimate. You can test your scale’s accuracy by weighing a known object like a 1 kg bag of sugar to make sure it reads correctly.
Keep in mind that home weights can vary by several ounces depending on timing, feeding, and diaper status. They’re useful for spotting general trends but shouldn’t replace the calibrated scales at your pediatrician’s office, which are designed for infant-level precision.
When Weight Is a Concern
A single weight measurement tells you very little. Growth is a pattern, not a snapshot. Pediatricians look at weight plotted over time on a growth chart, watching for a baby who consistently follows their own curve. A baby at the 10th percentile who has always been there is not underweight. A baby who drops from the 60th percentile to the 15th over two or three visits is worth a closer look, even if their current weight falls within the “normal” range.
The WHO standards flag weights below the 2nd percentile or above the 98th percentile as potentially abnormal, but doctors always interpret these numbers alongside the full picture: family size, birth history, feeding patterns, developmental milestones, and overall health. A baby who is active, meeting milestones, and eating well is rarely a cause for worry regardless of where they land on the chart.